flippy flippy flippy
i think top third of head looks cool couldn't you joint it staight with the bottom third (ditch the face in the middle).
There's so many great details here! It's too bad that it's shaded as it is (mirrored, low-contrast, indefinite lightsource). Were there a more well-defined lightsource and deeper shadows, I feel like it could go from good to extremely good. The dithering also feels a bit excessive, though you certainly did stretch your 16 colors.
The head is Ansurasax of Bastard!, Kazushi Hagiwara.